Fastening for inherently slippery fabric on tubular metal furniture



March 14, 1961 M. l. THO FASTENING FOR INHERENTLY MAS 2,974,721

SLIPPERY FABRIC ON TUBULAR METAL FURNITURE Filed June 17,

INVENTOR. MORTON THO/719$ BY M United States Patent FASTENING FOR INHERENTLY SLIPPERY FABRIC ON TUBULAR METAL FURNITURE The invention herein disclosed relates to fastenings for securing the supporting fabric material to metal chair frames and the like such as disclosed in Patents 2,817,392 of December 24, 1957, and 2,856,990 of October 21, 1958, in which the material is snubbed about a sheet metal plate which has one or more hooks snapped into engagement into an appropriately located slot or slots in the tubular frame.

Some of the plactic materials used for the supporting fabric have an inherently slippery characteristic desirable for seating. and supporting purposes but rendering it difiicult to secure the same without cutting, tearing or injuring the same.

Objects of the present invention are to provide a reliable and satisfactory fastener for holding such materials and particularly. to provide such a fastener which will automatically take hold and secure the material all the more firmly, without cutting or otherwise injuring the same as load on the structure is applied or increased.

Accordingly the invention comprises a sheet metal fastening plate curved to approximate the curvature of the tubular furniture frame, having a substantially smooth snubbing edge about which the material may be looped, a material impinging opposite edge substantially parallel to the snubbing edge and between these edges a hook or prong adapted to enter a slot in the tubular frame and inclined on an acute angle adapted to wedge the plate all the more firmly toward the frame as the load on the plate is increased, thus in effect to rock the holding edge of the plate into better and more positive holding engagement in the material.

Other desirable objects attained by the invention and further novel features through which purposes of the invention are accomplished are set forth and will appear in the course of the following specification.

The drawing accompanying and forming part of the specification is illustrative of a presently preferred embodiment of the invention but structure may be modified and changed within the true intent and scope of the invention as hereinafter defined and claimed.

Fig. 1 in the drawing is a broken front view of a chair back having the invention incorporated therein.

Fig. 2 is a broken vertical sectional view of the chair as on substantially the plane of line 2-2 of Fig. 1.

Figs. 3 and 4 are enlarged broken sectional details taken on substantially the plane of line 34 of Fig. 2 showing the fastener first in the position of engagement with the frame and then as wedged into interlocked holding engagement with the underlying fabric by load applied to the supporting portion of the fabric.

Fig. 5 is a plan View of the fastener as seated in the looped end of-the fabric, the latter partly broken away and appearing in section.

The invention is shown applied to a chair construction having a tubular seat frame 7 and a tubular back frame 8.

These frames are slotted at 9 to receive the prongs of the fastener plates which secure the strips of webbing 10 providing the seat and back supports.

The fasteners consist in each instance of a sheet metal plate 11 transversely curved to the approximate curvature of the tubular frame, having a relatively smooth straight continuous snubbing edge 12 about which the fabric is looped at 13 and an opposite substantially parallel positive gripping and holding edge 14, toothed, cor: rugated, roughened or otherwise finished to dig into the material without cutting, tearing or otherwise breaking into or weakening the fabric structure.

- Between these opposing, snubbing and fabric impinging edges there is provided a hook or prong 15 extending away from the snubbing edge at the inner concave side of the plate and extending toward the locking or holding edge at an acute-angle such as shown in Figs. 3 and 4 which will enable the prong to wedge the plate toward the tubular frame as pull is applied over the snubbing edge of the plate.

Fig. 3 shows the plate or clip as it is first applied with the toothed edge 14 biting into the underlying end portion 16 of the material.

Fig. 4 shows how pull applied to the fabric with a load or force indicated by the arrow will have a tendency to shift the plate in a left handed direction and thus cause the acutely angled hook 15 to draw the plate in closer against the material, thus locking the material all the more firmly in place on the frame.

By providing a multiplicity of teeth along the holding edge the gripping effect is spread across the full width of the material and thus positive securing is obtained without cutting or breaking into the surface of the material.

This is particularly important for plastics of the modern smooth slippery type which have relatively hard lowfriction coefficient surface.

The holding edge 14 instead of being continuously toothed or roughened may have an unbroken straight intermediate portion such as shown at 17 in Fig. 5 opposite the point of the hook element, relieving this portion of some of the holding load so as not to Weaken the intermediate portion of the plate at 18 out of which the hook or prong is cut.

The end portions of the clip at opposite sides of the hook or prong are shown as reinforced by the diagonally inclined embossments 19.

While shown as a fastening for strips of webbing after the manner of the earlier Patent 2,817,392 it will be appreciated that the fastener may be made up as a continuous length fastener for wide fabric as disclosed in the second Patent 2,856,990.

In the latter form the plate is lengthened usually to the full width of the fabric and provided with a multiplicity of the holding prongs.

In both forms the prong or prongs act as a fulcrum center causing the plate to rock into tight holding engagement with the fabric, the acute angle of the prong wedging and holding the plate in interlocked close-fitting engagement with the frame where it is out of sight but yet may be readily released if need be by prying the looped end away from the frame.

The fastening may be easily applied without need of tools and ordinarly may be removed by simply slipping the point of a screwdriver beneath the snubbing edge and applying the slight force needed to pry the plate loose from the frame.

While generally preferred to have the plate of corre sponding curvature it may be made with slightly different curvature to emphasize the tendency of the holding edge to bite into the material. This holding engagement is ordinarily so secure as to eliminate any need for extending the inner end of the material to under-lap 3 the supporting material as illustrated in Patent No. 2,817,- 392. This is an advantage resulting in the saving of the material.

These fastener plates can be produced at low cost by simple stamping operations on strip sheet metal.

What is claimed is:

Fastening for securing inherently slippery fabric on tubular frame furniture comprising in combination with a tubular frame member having a slot in the wall of the same, a fastener plate of rigid thin sheet material transversely curved to the approximate curvature of said tubular frame member and having elongated side edges substantially equal in extent to the Width of the fabric to be secured to the frame member, fabric material of a slippery character extending over the outer convex face of said plate and looped over the outer edge of said plate and extended over the inner concave face of the plate beyond the inner edge of the plate, said plate being disposed over the slotted wall portion of said tubular member with that portion of the fabric extending over the inner face of the plate disposed between said plate and the wall of the member, said outer edge of the plate being smooth and continuous and forming a snubbing edge for the fabric looped over the same and said inner edge of the plate being toothed and directed by the transverse curvature of the plate toward that portion of the fabric extended beyond said edge and disposed between said toothed edge and the Wall of the frame member in back of the same and whereby said toothed edge constitutes a holding edge gripping the snubbed inner portion of the fabric against the wall of the tubular frame member and a slanted prong on the inner concave face of the plate extending through the inner layer of the fabric and projecting on an incline through and engaging the edge of said slot in the frame member at an angle drawing the plate and the fabric snubbed and held thereby into solidly gripped engagement with the frame member.

References Cited in the file of this patent UNITED STATES PATENTS and: 

